Lubricant



Patented July 5, 1938 V UNITED: STATES PATENT OFF-ICE 1 No Drawing.

16 Claims.

The present invention relates to improvements in greases, and will befully understood from the following description thereof.

This application is a continuation-in-part of 5 my copending applicationSerial Number 412,929. The present invention relates to greases of anunotuous character consisting principally of a lubricant oil and agelling metallic soap, such-- greases having a great adherence to theparts to be lubricated and a strong resistance to being squeezed outunder load. Ordinarily lead soaps are employed in such greases, such asthe lead soaps of oleic acid, fish oils, stearic acid, castor oil,linseed oil, degras, resin, or naphthenic acids. 5 Other gellingmetallic soaps which may be employed are the similar soaps of aluminum,calcium, zinc, copper, manganese, magnesium and the like. In general,the use of the lead soaps, for example, the naphthenate, oleate or fishoil soaps, is preferred. However, soaps of other metals or mixtures ofsoaps of difierent metals or other gelling or body-imparting materialscapable of imparting to the oil the desired characteristics may beemployed. Water-soluble soaps such as sodium soaps may be used, but

with such soaps, particular care must be used to prevent theformation ofsoluble oils suchas cutting oil. A

In the manufacture of such greases, wherein adhesion and resistance tosqueezing out under load are desired, it is necessary to incorporateinto the mineral lubricant oil employed substantial quantities of thenon-setting, gelling soap. For example, the proportions desired may beas high as from 20% to 60% of the soap, but such proportions of the soapresult in an extremely heavy, viscous material which does notreadilyflow and the use of which may be entirely impractical in bearings withsmall clearance or gpwhen there is occasional or continuous exposure toa low temperature. The low fluidity of suchgreases has renderednecessary the use of relatively small proportions oi, the soap, or hasprevented entirely the use of such compounds.

I have found that a fluidity of s'uchcompounds may be modified byincorporating therein a small proportion, rangingordina'rily from to10%, 01' organic oil-miscible solvents having a boiling point of 80C.or' higher, and preferably of from 150 to 250 C. Theseorganic'solven'ts, which are completely miscible with the oil-soapcompound, are of the type now generallydesignated as lacquer solvents.For example, I have successfully employed such oil-miscible solvents asethylene dichloride, dichlorethylether, diethyleneglycol, themonoallwlethers oi. ethyleneglycol and di-. ethyleneglycol and theiresters, such as ethylenelycol, monoethylether, ethyleneglycol,monoethylether acetate, ethyleneglycol monobutylether, diethyleneglyoolmonoethvlether, diethyl- Application December 11, 1934, Serial No.757369 ene glycol monobutyiether,triethanolamine, and the like.Equivalent solventssuch as phenyl chlorides, including monochlorbenzene, orthodichlor benzene, and trichlor benzene may'likewise beused. The phenyl chlorides, and particularly monochlor benzene arepreferred for calcium basegreases. For, example, I have found 5ethyleneglycol monoethylether, dichlorethylether, and ethylenedichloride to be particularly desirable in increasing the fluidity ofsuch compounds. The proportion of such solvents which may be employedvaries, depending upon the characteristics of the compound in which itis incorporated and the characteristics desired in the final product.Thus, from to 1% of the solvent has an appreciable effect in reducingthe viscosity and increasing the fluidity of the compound. Ordinarily,for example, with a content of lead fish oil soap, say of 5 to 30%, from3 to 5% of such a solvent, for example, dichlorethylether orethylenedichloride may be employed. With the com pounds containinghigher proportions of the soap, say 30 to up to.10% or even more of thesolvent may be 'incorporated- The solvent may be selected and theproportions thereof adjusted in accordance with the desired use. Forexample, in bearings with, smaller clearances, more solvent may beemployedto secure a greater fluidity, and a more volatile solvent may beemployed to permit its rapid evaporation.

Occasionally, the compounds containing the solvent may show somesettling on long standing, as in compounds containing a small amount ofthe soap'in a low-viscosity oil and I have found that this may beprevented by incorporating into the composition a small proportion of ahigh boiling organic ester, having preferably a boiling point of from250 to 450 C. or higher. For example, I have employed 'for thispurposesuch esters as trlcresyl phosphate, butyl phthalate, amyl phthalate,dibutyl phthalate,butyl stearate, ethyl acetate, or the like. Dibutylphthalate' I have found to be particularly effective. From to 2 or -5%of such high boiling esters, while miscible with the oil and the oilsolvent employed, are ordinarily suiiicient.

As will be readily understood, the lubricant oil employed and thespecific metallic soap will be selected in accordancewith the practiceof the art to secure the desired type of lubrication. Thus, for smallhigh speed units, the gears and bearings require a relatively'lowviscosity mineral oil, say 75. to 150 sec. Saybolt at F., whilefor-heavier duty gears and bearings, higher viscosity oilsmay beemployed and larger proportions of the soap may be present. The pres Vence of the solvent and thestabilizing material in accordance with thepresent invention does not materially alter the lubricatingcharacteristics of the compound apart from markedly in- 6 creasing itsfluidity and extending its ada bility in use. The compound retains itsdesirable qualities of adherence to metal and resistance to squeezingout under load. The solvent may be in part dissipated in use, but sincesuch loss occurs-after application of the lubricatingcompound, andqafterits penetration into the working parts of the bearing or gearing, itdoes 'not adversely affect the value of the compound,

but is, in fact, frequently desirable.

- A sodium soap grease may be prepared containing 10-50% of a sodiumsoap such as oleate, stearate or the like (preferably tallow fat acids)and the balance mineral oil of the desired viscosity. A typical greasewill contain 30% sodium soap and 70%, of a heavy steam-refined cylinderstock mineral oil, for example, having a viscosity of 200 Saybolt at 210F. Such a grease will be extremely hard, and particularly suitable foruse in lubricating roll neck bearings. With the par ticular sodium soapdescribed 2%% of butyl Carbitolis preferred as a solvent.

and desire to secure by and a non-setting, gelling soap, said compoundincluding a minor proportion of an aliphatic oil-misciblegrease-compatible organic solvent whereby the-fluidity thereof isincreased, and a stabilizing organic ester, selected from a groupconsisting of tricresyl phosphate, butyl phthalate,

amyl phthalate, dibutyl phthalate, butyl stearate, and ethyl acetate.

2. An adherent, fluid, lubricating compound composed'principally of aviscous mineral oil and a non-setting, gelling soap, said compoundincluding a minor proportion of an aliphatic oil-misciblegrease-compatible organic solvent,

whereby the fluidity thereof is increased, and a stabilizing organicester having a boiling point between 250 and 450 C., selected from agroup comprising tricresyl phosphate, butyl phthalate,

amyl phthalate, dibutyl phthalate, butyl stearate,

and ethyl acetate.

3. An adherennlubricating compound composed principally of a viscousmineral oil and a non-setting, geliing' soap, said compound in-- cludinga'minor proportion of an oil-miscible grease-compatible'organic solventcontaining a monoalkyl-glycolether group, whereby the fluidity thereofisincreased, and a high boiling organic ester selected from a groupconsisting of tricresyl phosphate, butyl phthalate, amyl phthalate,dibutyl phthalate, butyl stearate and ethyl acetate.

4.'An adherent, fluid lubricating compound composed principally of avisco s mineral oil and a non-setting'gellingsoap, said compoundincluding dichlorethylether in quantity suflicient to increase thefluidity thereof.

5. An adherent, fluid lubricating compound composed principally of aviscous mineral oil and'a non-setting, gelling soap, said compoundincluding diethylene'glycol monobutyl ether in quantity sufficient toincrease the fluidity thereof.

6. An adherent, fluid lubricating compound composed principally of aviscous mineral oil and a non-setting, gelling soap. said compoundincluding ethylene dichloride'in quantity sumcient to increase thefluidity thereof.

7. An adherent, fluid lubricating compound composed principally ofviscous mineral oil and -a non-setting, gelling soap, said compoundincluding a minor proportion of ethylene dichloride and a smallproportion of dibutyl phthalate. 8. An adherent, lubricating compoundcontaining a mineral oil, from. 10 to 30% of a lead soap, and from 3 to5% of an oil-miscible grease compatible hydrocarbon derivative solventcapable of increasing the'fluidity thereof without materially affectingthe lubricating properties of the lubricating compound.

9. An adherent, lubricating compound composed of a viscous mineral oiland from to 30% of a lead soap, said compound including from 3 to.5% ofan aliphatic oil-miscible greasecompatible organic solvent and from A to3% of a high boiling point ester, selected from a group consisting. oftricresyl phosphate, butyl phthalate, amyl phthalate, dibutyl phthalate,butyl stearate and ethyl acetate.

, 10. A method of modifying the fluidity of greases composed principallyof viscous mineral oil and a metallic soap, said soap being present inan amount suflicient to produce a grease structure of the characterproduced in a lead soap by the presence of approximately 5-30% of thelead soap, which consists in adding an oil-miscible solvent of the classconsisting of ethylenedichloride,

dichlorethylether, diethyleneglycol, the monoalkyl ethers of theethyleneglycoland diethyleneglycol and their esters and phenylchlorides.

I 11. An adherent fluid grease composed principally of a viscous mineraloil and a metallic soap, thesoap being present in an amount sufllcientto produce a solid grease structure, and said conpoundincluding a minorproportion of an oilmiscible organic solvent of the class consisting ofethylenedichloride, dichlorethylether, diethyleneglycol, the monoalkylethers of ethyleneglycol and diethyleneglycol and their esters, andphenyl chlorides, whereby the grease is rendered fluid without materialimpairment of its grease characteristics.

12. An adherent fluid grease composed principally of a viscous-mineraloil and a gellingmetallie soap, the soap being present in that amountsuflicient normally to produce a grease solid at normal temperatures andsaid grease compound including a small proportion of a liquidoil-miscible, grease-compatible, hydrocarbon derivative organic solvent,whereby the'ffluidity thereof is markedly modified without materiallyaffecting the lubricating faculties of the grease compound.

13. A grease as set forth in claim 12, in which the organic solvent hasva boiling, point from 80 C. to 250 C.

14. A compound as set forth in claim 12, in which the organic solvent ispresent in an amount from A to 10% of the grease.

' 15. A compound as set forth in claim 12, in which the solvent containsa monoelkylglycolether group.

16- A compound-as set forth in claim 12, in

which the organic solvent is diethyleneglycolmv

